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    <title>Document</title>
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<body>
    <script>
        var obj = {
            name: "lyy"
        }
        function foo() {
            console.log('foo函数', this.valueOf());
        }
        // 执行函数并且this指向obj对象
        // foo.call(obj)
        foo.call(123)
    </script>
</body>

</html>